1. Technical Field
The present invention relates to augmentors for gas turbine engines in general, and to cooled augmentors in particular.
2. Background Information
Augmentors, or "afterburners", are a known means for increasing the thrust of a gas turbine engine. Additional thrust is produced by an augmentor when oxygen contained within the core gas flow of the engine is mixed with fuel and burned. The temperature of the core gas flow within the augmentor requires the inner liner of the augmentor be cooled. Typically, bypass air at a temperature less than that of the core gas flow is used to cool the liner. The bypass air is supplied via an annulus between the liner and outer casing of the augmentor and enters the augmentor through apertures within the liner. Cooling occurs as the air passes through the apertures and subsequently passes along the inner surface, or "hot side", of the liner. Within most of the augmentor, this type of cooling arrangement suffices because of the relatively thin profile of the liner. At the aft end of the augmentor, however, fingerseals and stiffening rings are attached to the inner lining. The cumulative stack of the liner, fingerseals, and stiffening ring minimizes the liner's exposure to cooling air and therefore the associated heat transfer. Consequently, thermal stress and low cycle fatigue are greater in the liner section about the fingerseal area.
What is needed, therefore, is an apparatus for sealing the aft end of the augmentor that avoids the aforementioned stress and fatigue.